the u.s. adult population, now say they belong to no church in particular. 6% of them are either atheist or agnostic. >> there's a yerng to find like minded people, so for people to have a conversation that's not taboo. >> reporter: we met him last month. he's the president of an atheist group in the bible belt, oklahoma city. >> we're not anti-religious, but we're pro secular. >> reporter: in the past three members membership has jumped from 300 members to well over 1,000. >> i do think it getting better. >> reporter: a college professor is one of them, she says the public mood on atheist is changing even here. >> there are still people who are marching in the parade at halloween yelling out you're going to hell and stuff like that. but there were more people who weren't. and i think that's going to keep going, i think that's the trend. >> reporter: researchers call them the nones, those who check the none box when asked to describe their religious affiliation, and they've doubled since 1990.